Urinary incontinence is a condition characterized by involuntary loss of urine, beyond the individual's control, due to the loss or diminution of the ability to maintain the urethral sphincter closed as the bladder fills with urine. Male or female stress urinary incontinence (SUI) occurs when the patient is physically or emotionally stressed. Such patients may also experience urge incontinence.
Fecal incontinence is a condition characterized by involuntary defecation or passage of feces through the anal canal due to injury to or weakness of one or more of the internal anal sphincter, the external anal sphincter, and the levator ani.
Implantable urethral and anal prosthetic sphincter systems have been disclosed in the prior art to treat incontinence that comprise an inflatable balloon that is either pillow or cuff shaped, a balloon reservoir/pressure source filled with a fluid, a pump, and interconnecting tubing. The balloon is implantable beneath or surrounding the urethral tract (at or near the bladder neck in female patients) or around the anal sphincter and is coupled through tubing to the balloon reservoir/pressure source and pump that are implanted subcutaneously. The pump may be manually actuated to inflate the balloon, which in turn compresses the urethral tract and prevents incontinence. The balloon may be deflated to allow voiding. Examples of such prosthetic sphincter systems are disclosed in U.S. Pat. Nos. 4,222,377, 4,571,749, and 5,562,598, and one such system comprises the AMS-800 Urinary Control System available from American Medical Systems, Inc.
Urethral tapes or slings have been developed that are implanted in a urethral sling procedure in which the urethral sling is inserted beneath the urethra and advanced in the retro pubic space, perforating the abdominal fascia. In one procedure, peripheral or end portions of the elongated urethral sling are affixed to bone or body tissue, and a central support portion of the elongated urethral sling extends under the urethral or bladder neck to provide a platform that compresses the urethral sphincter, limits urethral distention, and pelvic drop, and thereby improves coaptation. Elongated “self-fixating” slings have also been clinically introduced for implantation in the body that do not require that the end portions be physically attached to tissue or bone and that rely upon tissue ingrowth into sling pores to stabilize the sling as disclosed, for example, in commonly assigned U.S. Pat. Nos. 6,382,214, 6,612,977, 6,641,524, 6,648,921, 6,652,450, 6,702,827, 6,802,807, and 6,911,003 and publications and patents cited therein.
The above-described slings comprise a central portion that is adapted to support the urethra, two end portions bracketing the support portion, a protective sheath or sheaths encasing at least the end portions, and connectors at the ends of the sling. Various ways of attaching a sleeve end and sling mesh end to a connector are detailed in the above-referenced '450 patent, for example. Further ways of attaching sling ends to sling implantation tools are disclosed in U.S. Patent Application Publication Nos. 2004/0087970, 2005/0245787, and 2005/0250977. The sling implantation tools are employed to form tissue pathways extending from a vaginal incision to two abdominal skin incisions and to draw the sling end portions through the pathways to dispose the sling free ends out of the skin incisions and the central portion around the urethra. The connectors are detached from the sling ends, and the sheaths are drawn out of the skin incisions, allowing the incisions to be closed.
Sling tension is typically adjusted at implantation sufficiently to take up any slack in the sling and impart at least a degree of increased tension to the urethra with the bladder empty. A surgical instrument may be placed between the sling central portion and the urethra, the sling ends drawn to tension and fully close the urethral tract, and the instrument withdrawn so that the uethra is relaxed sufficiently to function. Alternative tension adjustment mechanisms that may be employed during implantation are disclosed in the above-referenced commonly assigned '827 and '921 patents.
Typically, such urethral tapes or slings are fabricated of a loose weave sling fabric or mesh that acutely engages tissue and encourages tissue ingrowth along the pathway through mesh pores to achieve chronic stabilization or “self-fixation. Tissue ingrowth takes about 2-3 weeks in the typical patient in the absence of any significant intentional or unintentional movement of the mesh. During this post-operative time, the patient monitors the degree of success achieved in ameliorating leakage and any discomfort that might occur if the applied tension is so high as to unduly slow voluntary urination.
If any such problems occur, it may be necessary to reopen the incisions to access and pull on the sling ends to tighten the sling central portion around the urethra or to reopen the vaginal incision to pull on the sling central portion to loosen the sling central portion around the urethra. Several approaches have been taken to simplify or reduce the need for such post-operative adjustments.
One tension adjustment complication arises from the fact that the loose weave sling mesh inherently stretches and elongates when tension is applied at the ends or central support portion to overcome resistance of the tissue bearing against the sling mesh along the tissue pathway. It is difficult to judge just how much tension to apply to achieve adequate tightening or loosening in the central support portion. In one approach to overcoming this complication disclosed, for example, in the above-referenced '450 patent, an elongated repositioning means, e.g., an elongated inextensible tensioning member, is incorporated extending in or along the sling mesh from near the sling ends to or through the sling central portion. Tension applied to the repositioning means is transmitted along the length of the sling so the sling mesh does not substantially stretch during initial positioning and any repositioning during the acute healing phase.
In another approach disclosed, for example, in U.S. Patent Application Publication 2006/0058574 (FIGS. 4a-4f), an expandable member or container is incorporated on or in the sling central support portion that can be inflated or deflated with bulking agent to apply more or less tension to the urethra. As stated therein, optionally, the container has a touchable internal valve element to permit the surgeon to palpate the area prior to injecting or removing the bulking agent. Alternatively, the bulking agent may be injected and removed via a two-way external port. When a bulking agent is injected into the container, the tissue between the mesh and urethra will expand. This results in two effects; a simple vertical lifting due to expansion and a vertical lifting due to stretching the outside of the mesh. A suitable bulking agent may be water or saline. A similar approach is disclosed in U.S. Pat. Nos. 4,019,499 and 6,786,861.
Other approaches that enable increasing tension of the sling central portion against the urethra involve shortening the lengths of the sling end portions as described, for example in the above-referenced, commonly assigned '921 patent. Mesh folds are formed in the sling end portions using filaments that extend through vaginal incisions externally of the body. Depending on the embodiment, the mesh folds can be released to decrease sling tension or be tightened to increase sling tension by pulling on the filament ends following the initial implantation procedure. In other embodiments, filaments are extended substantially through the lengths of the sling end portions and extend from the vaginal incisions. The filaments may be gripped and pulled to tighten the mesh in the sling end portions to increase overall sling tension.
In still another approach disclosed, for example, in U.S. Patent Application Publication 2006/0058574 (FIGS. 5a-5c), the mesh sling or tape is further modified to include a mechanical adjustment means to adjust the length of the tape in the end portions on either side of the central portion after the tape has been implanted in the tissue pathways. The mechanical adjustment means incorporate a tie-wrap mechanism or sutures and one-way suture retaining devices of the type disclosed in U.S. Pat. No. 5,669,935 located along the tape on either side of the central portion. In each case, one suture end is affixed to the tape and extends along it and through a suture retaining device affixed to the tape closer to the central portion. The sutures or tie-wrap are not tensioned at implantation, and the tie-wrap or suture free ends extend through the vaginal incision. If the tension on the urethra is too light as determined during the acute healing phase, the surgeon may grasp and pull on the tie-wrap or suture free ends to shorten the lengths of the tape end portions and thereby increase sling tension. The exposed suture or tie-wrap ends may be severed during chronic implantation.
In yet another approach, tape or sling ends or the end of a tensioning cable coupled to a urethral support mechanism are coupled to an adjustment mechanism that is chronically implanted subcutaneously and can be accessed to adjust sling tension. See, for example, commonly assigned U.S. Pat. No. 4,969,892 and further U.S. Pat. Nos. 5,474,518 and 6,117,067 and the REMEEX® readjustable sling by Neomedic, Intl. (www.remeex.com). Ratchet or gear adjustment mechanisms that are accessed using a driver inserted through the skin and thereby rotated to increase or decrease sling tension are disclosed in the '892 and '518 patents. An inflatable/deflatable elastic chamber, adjustment mechanism that incorporates a fill port that is penetrable by a syringe needle advanced through the skin is disclosed in the '067 patent. The adjustment forces are applied to the sling ends and must be transmitted through the sling to effect any change in tension along the sling central portion adjacent the urethra.
Further sling tension adjustment mechanisms and techniques involve adding tensioning filaments to the sling free ends and extending the elements through the skin incisions and into engagement with buttons or pads implanted subcutaneously engaging a muscle or rectus fascia layer and/or having tissue engaging elements or anchors along the filament or at the sling ends that engage subcutaneous tissues as disclosed, for example, in U.S. Pat. No. 6,911,002 and in U.S. Patent Application Publication Nos. 2005/0004576 and 2006/0089525.
Although effective in alleviating SUI, further improvements in urethral and anal slings to post-operatively adjust tension applied to the urethra and anus are desirable.